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In a semiconductor diode, barrier potential offers opposition to only————–.

Solution: A depletion layer is formed across the junction of a semiconductor diode. Barrier potential offers opposition to only majority carriers... View Article

A block of mass m is attached with a massless spring of force constant k. The block is placed over a rough inclined surface for which the coefficient of friction is μ=3/4. The minimum value of M required to move the block up the plane is (Neglect mass of string and pulley and friction in pulley).

Solution: Let mass M descends x meter to lift the load then kx = mgsinθ + μmgcosθ kx=6m+6m kx=12m Now, applying work energy... View Article

Electromagnetic wave travels in medium with speed of 2×10^8m/s. The relative permeability of the medium is 1. Find the relative permittivity of the medium.

Solution: Speed of the electromagnetic wave in a medium is given by =2.25... View Article

Fission of nuclei is possible because the binding energy per nucleon in them:

a) Decreases with mass number at high mass numbers b) Increases with mass number at high mass numbers c) Decreases with mass number at low mass... View Article

Young’s double slit experiment is first performed in air and then in a medium other than air. It is found that the 8th bright fringe in the medium lies where the 5th dark fringe lies in the air. The refractive index of the medium is nearly:

Solutions:... View Article

The primary and secondary coils of a transformer have 50 and 1500 turns respectively. If the magnetic flux linked with the primary coil is given by ϕ=ϕ0+4t, where ϕ is in webers, t is time in seconds and ϕ0 is a constant, the output voltage across the secondary coil is:

Solution:... View Article

A current of 2A is increasing at a rate of 4A/s through a coil of inductance 2H. What is the energy stored in the inductor per unit time?

Solution: Potential difference across coil is V=2*4=8V Energy stored per unit time is given by P=Vi =8*2 = 16 J/s... View Article

Two identical capacitors each of capacitance 5μF are charged to potential 2 KV and 1 KV respectively. There negative ends are connected together, when the positive ends are also connected together, the loss of the energy of the system is

Solution:... View Article

A capillary tube of glass is taken from the Earth’s surface to the surface of the Moon. The rise of the water column on the Moon (given contact angle between glass and water is =0 degree and acceleration due to gravity on the Earth is 6 times that of the Moon) is:

Solution: Six times that on the Earth’s surface.... View Article

A square wave current switching rapidly between +0.5 amperes and -0.5 amperes is passed through an AC ammeter. The reading shown by ammeter is ——————-

Solution:... View Article

A roller coaster is designed such that riders experience “weightlessness” as they go round the top of a hill whose radius of curvature is 20 m. The speed of the car at the top of the hill should be between

Solution: The speed of the car at the top of the hill should be between 14 and 15.... View Article

Light is incident on the interface of glass and air as shown in the figure. If green light is just totally internally reflected then the emerging ray in air contains.

Solution: We know that white light is composed of a band of colours arranged in red, orange, yellow, green, blue, indigo, and violet. When the... View Article

In a committee, 50 people speak Hindi, 20 speak English and 10 speak both Hindi and English. How many speak at least one of these two languages?

Solution: Let n(H) be the number of people speaking Hindi and n(E) be the number of people speaking English. n(H) = 50 n(E) = 20 n(H⋂E)... View Article

In a class there are 35 girls and 20 boys and the total average weight of class is 38 kg. Total average weight of boys is 52 kg. Find the approximate average weight of girls ?

Solution: Total number of boys and girls = 35+20 = 55 Total average weight of class=38 kg Total weight of students = 38×55 =... View Article

Angle between vectors a and b where a, b and c are unit vectors satisfying a + b + √3c = 0 is

Solution: Given a + b + √3c = 0 a + b = -√3c Squaring both sides |a|2+|b|2+2|a||b| cos θ = 3|c|2 1+1+2 cos θ = 3... View Article

If one zero of the polynomial p(x) = (a²+9)x² +45x + 6a is reciprocal of the other, find the value of a

Solution: Given p(x) = (a2+9)x2 +45x + 6a Let k and 1/k be the zeros of the polynomial. Product of the roots = k(1/k) = c/a => 1 =... View Article

In given figure ABC is a right-angled triangle at B. Let D and E be any points on AB and BC respectively. Prove that (AE)² + (CD)² = (AC)² + (DE)².

Solution: ABE is a right angled triangle. (AE)2 = (AB)2 + (BE)2…(i) DBC is a right angled triangle. (DC)2 = (BD)2 + (BC)2…(ii) Adding (i)... View Article

If A = { a, b, c, d, e }, B = { a, c, e, g } and C = { b, e, f, g }, verify that:

(a) A⋂(B-C) = (A⋂B) - (A⋂C) (b) A- (B⋂C) = (A - B) ∪ (A - C) Solution: Given A = { a, b, c, d, e } B = { a, c, e, g } C = { b, e,... View Article

If the x-intercept of some line L is double as that of the line, 3x+4y = 24 and the y-intercept of L is half as that of the same line, then the slope of L is

Solution: Given line is 3x+4y = 24 Converting to intercept form, (3x/24) + (4y/24) = 1 => (x/8) + (y/6) = 1 Here x intercept is 8... View Article

If a point C lies between two points A and B such that AC = BC, then prove that AC = ½ AB. Explain by drawing the figure.

Solution: Given that we have a point C on AB such that AC = BC. Add AC on both sides AC + AC = AC + BC 2AC = AC + BC 2AC = AB(since AC+BC... View Article

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